The versatility of material handling devices is in part provided by their suitability for use under severe operating conditions. Accordingly, such equipment is ordinarily designed to be quite rugged for reliable and trouble-free operation under the rigorous service conditions to which it is subjected. Components of such equipment are selected to resist failure even though vibration and shock loading can be high, and even though such equipment is usually operated in and around dirt, mud, or other debris which can be potentially damaging to the equipment.
Many types of material handling equipment include hydraulically operated implements for effecting material handling functions. A typical piece of equipment includes a hydraulic fluid pump which supplies pressurized hydraulic fluid to hydraulic actuators for selective operation of a implements such as front-end loaders, backhoes, and like articulable devices. As will be recognized, the nature of such equipment frequently makes it necessary to route hydraulic fluids supply lines in relatively unprotected locations. Additionally, the articulable nature of the implements on such equipment frequently mandates the use of flexible fluid supply lines such as hoses and the like. In view of the typically severe conditions to which such equipment is subjected, and because of the high pressure of fluid carried by such fluid supply lines, deterioration and failure of a supply line can occur. While such an occurence usually results in no more than undesired downtime for the equipment for appropriate repair, there are instances where leakage of a fluid supply line can create greater problems. For example, the failure of a fluid supply line which is supplying fluid to an actuator associated with an implement working against the force of gravity (such as a loader bucket) could result in highly undesirable loss of control of the implement.
Therefore, it is extremely desirable to provide a hydraulic system for operating a fluid actuator wherein the system is adapted to detect the occurances of leaks therein, and respond in a manner which prevents undesired loss of control of the implement associated with the actuator.